Salivary gland tumors, as well as other malignancies of the head and neck, such as squamous cell carcinoma and esthesioneuroblastoma, may invade the skull base by proximity or by perineural invasion.[3, 2, 4] These tumors cause cranial nerve paralysis by invasion or direct extension; accompanying pain is due to erosion of the involved structures. Involvement of the periosteum or dura is the primary mechanism of direct tumor spread and the causative pathology.
One of the most comprehensive reported series of bone tumors came from the Mayo Clinic. Of the 7975 bone tumors in the series, 4% involved the skull (excluding the mandible, maxilla, and nasal cavity), 19% were benign, and 81% malignant. As the Mayo Clinic is a tertiary referral center, some degree of selection bias probably was in effect.
Other studies estimate that skull tumors constitute 1% of bone tumors.
Bone-forming tumors: Osteosarcoma is the second most frequent malignant skull tumor after multiple myeloma, accounting for 13% of this series.
Cartilage-forming tumors: Chondrosarcoma is the third most common malignant bone tumor, with a frequency of 11-12.5%.
Connective tissue tumors: Fibrosarcoma accounts for fewer than 5% of these tumors.
Histiocytic tumors
Ewing sarcomas account for about 5% of these tumors.
Giant cell tumors (osteoclastomas) also account for about 5% of these tumors.[5]
Tumors of blood or blood vessel origin: Angiosarcomas are rare malignant tumors.
Squamous cell carcinomas of the temporal bone occur with a frequency of 1 case per 25,000 patients with chronic otitis.
Mortality/Morbidity
See the list below:
Recurrent sinusitis is a common complication of tumors affecting the sinuses.
If the excision is incomplete, many tumors can recur.
Cranial nerve compression can occur in skull-base tumors.
Metastasis
Death
Persistence of disease after treatment is a serious problem, since it leads to persistent morbidity; patients have a significant decrease in the quality of life prior to dying from the disease. The aim of therapy is to control the disease locally.
Race
No racial predilection exists for any malignant skull tumor.
Sex
See the list below:
Most malignant skull tumors have no sex predilection (except possibly metastatic disease).
Fibrosarcoma, Ewing sarcoma, and chordomas occur more frequently in men than in women.
Age
See the list below:
Bone-forming tumors and fibrosarcomas usually present in middle-aged adults.
Cartilage-forming tumors may present at any age, with a peak during the second decade.
Ewing sarcoma is a disease of childhood, whereas giant cell tumors are seen mainly between the second and fourth decades.[6]
Angiosarcoma can present at any age.
Multiple myeloma is more common in older adults.
Chordomas usually present in the third or fourth decade.
Metastatic tumors follow the pattern of the primary tumor.
Squamous cell carcinomas occur in the older adult, often in the sixth decade.
Esthesioneuroblastomas occur in young adults in their 30s and 40s.
Mass without pain as in multiple myeloma and osteosarcoma
Nonspecific headache
Cranial nerve deficits: These are seen in giant cell tumors, angiosarcomas, and chordomas, as well as in tumors of the head and neck with propensity for perineural spread, such as tumors of salivary origin (eg, adenoid cystic carcinomas, adenocarcinomas, mucoepidermoid carcinomas).
Fever and malaise
Location of the tumor
Although the location of the lesion is of little value in making the diagnosis, certain tumors prefer the convexity more than the skull base and vice versa; lesions of developmental origin have a propensity for the midline.
Chondrosarcomas, giant cell tumors, angiosarcomas, and chordomas usually involve the skull base.[7]
Osteosarcomas and fibrosarcomas commonly are found in the mandible and maxilla.[4, 8]
The remainder usually involve the calvaria.
Patients may have a history of previous malignancy, fibrous dysplasia, or Paget disease.
Multiple, small, nonmarginated lesions usually indicate metastatic disease.
The absence of peripheral sclerosis strongly favors a malignant tumor.
The differential diagnosis includes the following:
Benign skull tumors
Encephalocele, meningoencephalocele, venous lakes of the skull, pacchionian depression
Cranial nerve deficits: These may include diplopia from involvement of cranial nerves III, IV, or VI; facial paralysis; hearing loss; vertigo; and sensation loss along the distribution of the trigeminal nerve. Voice changes and swallowing disorders, with or without tongue fasciculations/paralysis, signify involvement of the cranial base at the jugular foramen with medial extension.
Most of the malignant skull tumors appear as radiolucent lesions, single or multiple, with irregular borders and no periosteal reaction.
Osteosarcomas appear as osteolytic soft-tissue extensions. They may have calcification within the lesion, no periosteal reaction, and poorly defined margins. The typical (but not frequent) appearance is the sun-ray picture.
Chondrosarcomas have no reliable radiological features and are characterized by lytic and sclerotic changes within poorly defined margins.
Fibrosarcomas are radiolucent lytic lesions with thinning and widening of the cortex, minimal periosteal involvement, and irregular margins.
Ewing sarcoma has a typical onion skin appearance with laminated periosteal changes. On CT scan, it appears as an isodense mass surrounded by a hypodense area and hyperostosis. It is also contrast enhancing.
Angiosarcomas are destructive lesions with cortical erosion and reactive ossification. On CT scan, they show heterogeneous enhancement with focal necrosis.
Plasmocytomas/multiple myelomas usually present as multiple lytic lesions that involve both the inner and outer tables, as well as the diploë from which they arise. On CT scan, depicted below, they are hyperdense, homogeneous enhancing lesions.
View Image
Head CT scan of a 60-year-old man with a history of multiple myeloma for 2 years, showing multiple lytic lesions that involve both the inner and outer....
Chordomas are soft-tissue masses usually seen in the nasopharyngeal area with various degrees of calcification. CT scan shows a soft-tissue mass with extensive bone destruction.
Metastatic neoplasms can be either of the following:
Osteoblastic, with sclerosis and thickening (eg, prostate, breast, bladder, hypernephroma)
Osteoclastic, with bone destruction and lucency (eg, lung, uterus, GI tract, thyroid, melanoma, neuroblastoma)
Giant cell tumors usually involve the sphenoid bone and commonly erode the sellar region. On brain CT scan, giant cell tumors are hyperdense, contrast-enhancing masses.
MRI
Most tumors are hypointense on T1-weighted images and hyperintense with heterogeneous signal on T2-weighted images.
Enhancement is common.
Bone scan: 99m technetium scan shows all malignant processes as hot areas.
Arteriogram: Tumors of vessel origin or associated with multiple myeloma have a high degree of vascularity.
Osteosarcomas are composed of a malignant spindle cell stroma, which directly produces osteoid or immature bone (osteoblastic, chondroblastic, or fibroplastic form).[9]
Low-grade chondrosarcomas (myxochondrosarcoma) are characterized by chondroid and immature cartilage deposition in areas of myxomatous change and cystic degeneration. The high-grade type (mesenchymal chondrosarcoma) is characterized by the absence of cartilage lobules and the presence of fibrosarcomatous areas. Groups of chondromatous cells lose their usual lobulation and begin to spindle out. Both types are vimentin positive.
Fibrosarcoma is characterized by varying amounts of collagen production and the absence of bone, osteoid, or cartilage. The medullary subtype has a better prognosis than the periosteal subtype.
Giant cell tumor (osteoclastoma) consists of a well-vascularized tissue mass of plump, spindle, or ovoid stroma cells together with uniformly dispersed, numerous, large, multinucleated giant cells.
Ewing sarcoma appears as uniform, densely packed small cells with indistinct cytoplasmic borders and many mitotic figures. They stain strongly with periodic acid-Schiff (PAS).[3]
Angiosarcomas (hemangiopericytoma or hemangioendothelioma) are characterized by the formation of irregular anastomosing vascular channels lined by one or more layers of atypical endothelial cells and pericytes, which have an anaplastic immature appearance.
Multiple myeloma is characterized by widespread osteolytic bone destruction by dense tumor cells that look like plasma cells clustered in close aggregates.[10]
Chordomas consist of physaliphorous cells (large, vacuolated, mucus containing) with a lobular arrangement and abundant extracellular mucoid tissue.
Metastatic tumors have the same or similar histologic features as their primary tumors.
Whenever possible, complete surgical excision is the treatment of choice for primary tumors (except multiple myeloma).
Preoperative embolization is recommended for angiosarcomas to reduce intraoperative blood loss. If other means cannot control tumor expansion, surgery is still an option in metastatic disease.
Radiosurgery, including Gamma Knife and CyberKnife, can be useful for some tumors.
Osteosarcomas - Primary form of treatment for secondary osteosarcoma, especially in elderly patients
Ewing sarcoma
Giant cell tumor
Multiple myeloma, if chemotherapy fails
Chordoma
Radiosensitive metastatic tumors
Not indicated for angiosarcoma and fibrosarcoma
Use in chondrosarcoma controversial
Chemotherapy also may be indicated. Chemotherapy should be administered under the direction of a hematologist and/or oncologist. Combinations of various drugs are used, including cisplatin, cyclophosphamide, carmustine (BCNU), and lomustine (CCNU).
Clinical Context:
Inhibits inflammatory reactions and pain by decreasing activity of enzyme cyclooxygenase, which in turn inhibits prostaglandin synthesis.
Osteosarcoma has a 5-year survival rate between 20% and 50%.
Chondrosarcoma has a 10-year survival rate of 30-80%, depending on the grade of the initial tumor.
Fibrosarcomas metastasize in 50% of cases, and the 10-year survival rate is 40%.
Ewing sarcoma has a 5-year survival rate of 40-65%.
Giant cell tumor has a recurrence rate of 30% in 2 years, but otherwise its prognosis is relatively good.
Angiosarcomas, if properly treated, have a cure rate of about 50%.
Chordomas, although difficult to resect completely, are slow-growing tumors and have a 5-year survival rate of 40%.
Myeloma survival rates vary depending on the grade. However, even in patients with widespread disease, complete remission can be achieved for up to 2-3 years (or longer).
Draga Jichici, MD, FRCP, FAHA, Associate Clinical Professor, Department of Neurology and Critical Care Medicine, McMaster University School of Medicine, Canada
Disclosure: Nothing to disclose.
Specialty Editors
Francisco Talavera, PharmD, PhD, Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference
Disclosure: Received salary from Medscape for employment. for: Medscape.
Jorge C Kattah, MD, Head, Associate Program Director, Professor, Department of Neurology, University of Illinois College of Medicine at Peoria
Disclosure: Nothing to disclose.
Chief Editor
Tarakad S Ramachandran, MBBS, MBA, MPH, FAAN, FACP, FAHA, FRCP, FRCPC, FRS, LRCP, MRCP, MRCS, Professor Emeritus of Neurology and Psychiatry, Clinical Professor of Medicine, Clinical Professor of Family Medicine, Clinical Professor of Neurosurgery, State University of New York Upstate Medical University; Neuroscience Director, Department of Neurology, Crouse Irving Memorial Hospital
Disclosure: Nothing to disclose.
Additional Contributors
Spiros Manolidis, MD, Associate Professor of Otolaryngology and Neurological Surgery, Columbia University
Disclosure: Nothing to disclose.
Acknowledgements
The authors and editors of Medscape Reference gratefully acknowledge the contributions of previous author Efstathios Papavassiliou, MD to the development and writing of this article.
Korten AG, ter Berg HJ, Spincemaille GH, van der Laan RT, Van de Wel AM. Intracranial chondrosarcoma: review of literature and report of 15 cases. J Neurol Neurosurg Psychiatry. July 1998. 65(1):88-92.
Mirra JM. Bone Tumors: Clinical, Radiological and Pathological Correlations. Lea and Febiger. 1989:
Sen CN, Sekhar LN, Schramm VL, Janecka IP. Chordoma and chondrosarcoma of the cranial base: an 8-year experience. Neurosurgery. Dec 1989. 25(6):931-940.
Head CT scan of a 60-year-old man with a history of multiple myeloma for 2 years, showing multiple lytic lesions that involve both the inner and outer tables as well as the diploë.
Head CT scan of a 60-year-old man with a history of multiple myeloma for 2 years, showing multiple lytic lesions that involve both the inner and outer tables as well as the diploë.
This head CT scan shows multiple lytic lesions of the skull involving both the inner and outer tables.
){kind=link}